The present invention relates to fine particle producing devices for reducing various kinds of materials to tiny particles. More particularly, it is concerned with fine particle producing devices in which particles of a substance contained in a liquid are caused to collide with each other under extremely high pressure, whereby the particles are emulsified, dispersed or reduced to finer particles in the liquid in an instant.
An example of conventional fine particle producing devices of this kind is an emulsifier disclosed in Japanese Unexamined Patent Publication No. 2-261525. In the emulsifier of the disclosure, two flow guiding blocks 90, 91 formed of a hard material are fitted side by side in a passage of a liquid mixture as shown in FIG. 26. The first flow guiding block 90 placed on an upstream side has a pair of through holes 90a, 90b and a first groove-like channel 90c connecting downstream openings of the two through holes 90a, 90b to each other. On the other hand, the second flow guiding block 91 mounted on a downstream side in close contact with the first flow guiding block 90 has a second groove-like channel 91c which runs at right angles with the first groove-like channel 90c and a pair of through holes 91a, 91b formed at both ends of the second groove-like channel 91c to allow the liquid mixture to flow downstream. When the liquid mixture is passed through the first and second flow guiding blocks 90, 91 under high pressure, a pair of streams of the liquid mixture directed in opposite directions are produced and the accelerated streams are caused to collide with each other to accomplish emulsification.
Although an abrasion-resistant material such as sintered diamond or artificial sapphire is used in the first and second flow guiding blocks 90, 91 in the conventional emulsifier, the first and second groove-like channels 90c, 91c remarkably wear out at their central portions where the streams of the liquid mixture collide at maximum speed. Thus, continuous operation of the emulsifier inevitably results in a rapid deterioration of the emulsifier's particle size reducing performance. It is therefore essential to replace the expensive flow guiding blocks 90, 91 from time to time to maintain emulsification performance. In these circumstances, there has been a need for flow guiding blocks which would provide a prolonged service life.
Another problem of the aforementioned conventional emulsifier is that it is impossible to reduce its physical size and thereby achieve energy savings, because a pump for pressurizing the liquid mixture can not be reduced in size and power without affecting the particle size reducing performance.